"Jim" wrote in message
...

It isn't dangerous to go skydiving (1-in-10000 chance of dying) once.
But "being a regular skydiver" where one jumps 100 or perhaps 1000
times in a lifetime gives you a much less trivial chance of being killed

Curious.

Not really.

If each jump carries a 1-in-10000 chance of dying, wouldn't
the 1000th jump also carry a 1-in-10000 chance of dying?

Yes, assuming the jumper survived the first 9999 jumps.

The probability of a person having successfully made 9999
jumps surviving his 10000th jump is very different (and less)
than the probability of a person who has made no jumps,
successfully making 10000 safe jumps.

The difference is that the first jumper's probability of the
first 9999 jumps are all 100% successfully, having been
made in the past.

If one flips a fair coin, over the long run there is a 1-in-2
chance of either side coming up.

Yes, but there isn't a 1-in-2 chance of flipping ten heads (say)
in a row. Except, of course, if one is improbable enough to
flip nine heads in a row, then the tenth head is 1-in-2.

If one flips a fair coin 1 million times do the odds of
either side coming up change?

One is not just loooking at the last flip, one is looking at
the accumulation of *all* the flips. For instance, it's no
good surviving the 10000th jump, if you didn't survive
the 7359th. :-) :-( :-S

"Don Tuite" wrote:

Actuary's numbers relate to populations, not individuals.

Does the parachute know whether 10,000 jumpers made one
jump each, or whether one jumper made 10,000 jumps?

--
Jeff Shirton jshirton at cogeco
dot ca

Keep thy airspeed up, lest the earth come from below
and smite thee. - William Kershner
Challenge me (Theophilus) for a game of chess at Chessworld.net!